This invention relates to a sheet material conveying and cutting apparatus of the type shown in prior U.S. Pat. Nos. 4,646,911 and 4,730,526 wherein an endless conveyor belt made up of interconnected slat-like support members is used to support and advance sheet material to and from a cutting station, and deals more particularly with improvements in such apparatus for causing the upper material supporting run of the conveyor belt to have and maintain a smooth and flat material supporting surface.
The conveyor of the invention has special utility and novelty in forming part of a cutting machine, such as shown in U.S. Pat. Nos. 4,646,911 and 4,730,526, for automatically cutting lay-ups or single layers of limp fabric or similar sheet material and having a vacuum means for holding down and compressing the sheet material during the cutting procedure. Therefore, the conveyor is herein disclosed and described and claimed in some claims as part of such cutting machine. However, the conveyor may also be used in other applications for supporting and advancing sheet material and there is no intention to limit the scope of the invention as defined by the broader claims of this application to only cutting machines.
In the use of endless conveyors for supporting and advancing sheet material it is often necessary, or at least very desirable, especially in the case of cutting machines, that the material be supported and advanced by a supporting surface which remains quite smooth and flat, both when the belt is moving and when not moving, so as to not disturb the shape or position of the supported and advanced material. Where the conveyor belt is comprised of relatively long interlinked support members extending transversely of the belt's path of movement a tendency exists for the support members to sag transversely under their own weight and the weight of the supported sheet material. Because of this and other factors, such as possible looseness in the joints pivotally connecting the support members to one another, the support members when positioned in the material supporting upper run of the conveyor may move vertically relatively to one another and/or may tilt out of a horizontal plane to cause the supporting surfaces of neighboring support members to become vertically misaligned with one another and to produce irregularities and discontinuities in the total composite supporting surface of the upper run.
The general object of this invention is therefore to provide a simple means for preventing the support members of the endless conveyor belt of a sheet material supporting and advancing conveyor apparatus from moving vertically relative to one another while positioned in the upper run of the conveyor and for thereby maintaining a smooth and substantially flat supporting surface for the sheet material.
Other objects and advantages of the invention will be apparent from the following detailed description of a preferred embodiment thereof taken in conjunction with the accompanying drawings and claims.